Figure 10.18 shows the phase-continued-frames case in which
relative phase is not preserved across FFT bins. As a result, the
amplitude envelope is not preserved in the time domain within each
frame. Figure 10.19 shows the spectrum of the same case,
revealing significant distortion products at multiples of the frame
rate due to the intra-frame amplitude-envelopedistortion, which then
ungracefully transitions to the next frame. Note that modulation
sidebands corresponding to multiples of the frame rate are common in
nonlinearly processed STFTs.